Meeting the caloric requirements of burn patients is an important aspect of patient care. Insufficient nutritional support can decrease immunocompetence and wound healing, whereas an excessive caloric burden can cause liver abnormalities and ventilatory distress. Existing estimates of caloric support can decrease immunocompetence and wound healing, whereas an excessive caloric burden can cause liver abnormalities and ventilatory distress. Existing estimates of caloric support, based on measurement of resting energy expenditure, may not be an accurate reflection of the total, 24 hour caloric requirements, since other aspects of patient care (surgery, dressing changes hydrotherapy for example), as well as voluntary movement, will have additional effects. Total energy expenditure has never been determined throughout the course of recovery from burn injury. The doubly labeled water technique is ideal for use in hospitalized patients since total energy expenditure can be measured by a non-invasive unrestricted method over extended periods of time. The technique involves administration of water, labeled with the stable isotopes deuterium and oxygen-18. Since deuterium is distributed only in body water, whereas oxygen-18 is distributed in water and carbon dioxide, the turnover rates of the two isotopes differ by an amount proportional to the carbon dioxide production rate. From this information total energy expenditure can be calculated. During 7 day intervals throughout the course of recovery from burn in jury we will determine daily resting energy expenditure by indirect calorimetry as well as total energy expenditure by the doubly labeled water method. The data collected will be used to: 1. Examine the relationship between resting and total energy expenditure throughout the course of recovery from burn injury. 2. Derive equations for predicting calorie requirements for nutritional support during recovery from burn injury from either the resting energy expenditure of from clinical observations.